All the current vacuum cleaners adopt single “dust collection” via inducing air from the air inlet. The efficiency of the motor for dust collection is relatively low. Particularly, the power of the motor for a portable cleaner or a current or future automatic cleaner which is powered by batteries is commonly relatively low, the suction is thus relatively small and so affects the performance of the cleaner as a household appliance. Moreover, there exists an outstanding inconvenience when using the conventional vacuum cleaner, i.e., the cleaner must be disassembled to remove the trash contained therein. Such problem is particularly notable for an automatic cleaner having sensors and small trash chambers.